#include"List.h"

LTNode* BuyLTNode(LTDataType x)
{
	LTNode* node = (LTNode*)malloc(sizeof(LTNode));
	if (node == NULL)
	{
		perror("malloc fail");
		exit(-1);
	}

	node->data = x;
	node->next = NULL;
	node->prev = NULL;

	return node;
}

LTNode* LTInit()
{
	LTNode* phead = BuyLTNode(0);
	phead->next = phead;
	phead->prev = phead;

	return phead;
}

void LTPrint(LTNode* phead)
{
	assert(phead);

	printf("phead<=>");
	LTNode* cur = phead->next;
	while (cur != phead)
	{
		printf("%d<=>", cur->data);
		cur = cur->next;
	}
	printf("\n");
}

void LTPushBack(LTNode* phead, LTDataType x)
{
	assert(phead);

	/*LTNode* tail = phead->prev;
	LTNode* newnode = BuyLTNode(x);

	newnode->prev = tail;
	tail->next = newnode;

	newnode->next = phead;
	phead->prev = newnode;*/

	LTInsert(phead, x);
}

void LTPopBack(LTNode* phead)
{
	assert(phead);
	assert(phead->next != phead);

	/*LTNode* tail = phead->prev;
	LTNode* tailPrev = tail->prev;
	free(tail);

	tailPrev->next = phead;
	phead->prev = tailPrev;*/

	LTErase(phead->prev);
}